Influence of roasting, gamma ray irradiation and microwaving on ruminal dry matter and crude protein digestion of cottonseed

Figures & data

Table 1. Chemical composition¹ and gossypol content (g/kg, mean ± standard error) of untreated and physically treated cottonseed.

Treatments^2	DM	CP	TP	NDF	ADF	EE	Ash	Gossypol
Untreated	918.4 ± 17.1	226.4 ± 11.7	210.4 ± 7.1	511.9 ± 13.4	409.3 ± 11.4	240.5 ± 10.3	42.1 ± 0.8	0.47 ± 0.01^a
R15	927.5 ± 21.8	227.6 ± 10.5	206.9 ± 9.0	516.8 ± 14.2	410.7 ± 11.2	238.7 ± 11.5	42.3 ± 0.9	0.40 ± 0.008^bc
R30	935.0 ± 22.7	232.9 ± 8.6	215.1 ± 10.4	508.3 ± 11.7	415.6 ± 9.6	237.7 ± 8.5	40.8 ± 0.7	0.37 ± 0.01^cd
γ15	910.9 ± 23.6	219.1 ± 9.4	208.9 ± 8.5	515.6 ± 12.9	405.7 ± 10.1	235.2 ± 9.2	44.3 ± 0.7	0.42 ± 0.01^b
γ30	921.8 ± 17.1	227.1 ± 10.6	210.7 ± 8.9	517.9 ± 12.2	411.8 ± 9.3	238.8 ± 10.3	45.2 ± 0.6	0.38 ± 0.01^c
γ45	918.3 ± 24.2	225.6 ± 8.9	212.2 ± 9.2	510.7 ± 13.1	413.6 ± 10.0	237.8 ± 12.1	42.7 ± 1.1	0.34 ± 0.008^d
MW2	922.4 ± 26.9	230.8 ± 8.3	211.3 ± 8.4	517.8 ± 11.6	408.5 ± 9.7	234.7 ± 8.1	41.5 ± 0.6	0.46 ± 0.01^ab
MW4	931.6 ± 25.1	223.5 ± 9.6	209.5 ± 7.4	515.8 ± 12.0	407.1 ± 10.4	234.5 ± 8.6	41.1 ± 0.9	0.43 ± 0.01^b
MW6	938.3 ± 20.8	228.7 ± 10.1	217.3 ± 8.6	512.5 ± 11.9	412.7 ± 9.8	229.8 ± 9.5	41.4 ± 1.2	0.41 ± 0.009^bc

Mean in the same column with different letters differ (p < 0.05).

1 DM = dry matter; CP = crude protein; TP = true protein; NDF = neutral detergent fiber; ADF = acid detergent fiber; EE = ether extract.

2 Different treatments were as follow: untreated = intact whole cottonseed, R15 = roasting for 15 minutes, R30 = roasting for 30 minutes, γ15 = 15 kGy gamma irradiation, γ30 = 30 kGy gamma irradiation, γ45 = 45 kGy gamma irradiation, MW2 = microwave irradiation for 2 minutes, MW4 = microwave irradiation for 4 minutes, MW6 = microwave irradiation for 6 minutes.

Table 2. Rumen degradation parameters of dry matter of untreated and physically treated cottonseed.

	Degradation parameters^2			Effective degradability at outflow rate (g/kg)
Treatments^1	a (g/kg)	b (g/kg)	c (h^−1)	0.02 h^−1	0.05 h^−1	0.08 h^−1
Untreated	31.7 ± 2.5^a	23.2 ± 2.8	0.152 ± 0.01^a	52.2 ± 3.0	49.2 ± 2.7^a	46.9 ± 2.5^a
R15	29.9 ± 2.4^ab	25.1 ± 3.5	0.13 ± 0.038^ab	51.6 ± 5.4	48.0 ± 4.8^ab	49.4 ± 4.5^a
R30	24.6 ± 2.7^c	26.0 ± 3.6	0.110 ± 0.02^ab	46.9 ± 3.3	42.6 ± 3.0^b	39.7 ± 2.9^b
γ15	31.9 ± 4.1^a	22.8 ± 3.4	0.130 ± 0.06^ab	50.4 ± 5.5	47.1 ± 5.3^ab	44.9 ± 4.9^ab
γ30	30.6 ± 3.4^ab	23.6 ± 2.8	0.116 ± 0.04^ab	49.0 ± 4.2	46.0 ± 4.2^ab	44.0 ± 3.0^ab
γ45	28.5 ± 1.9^ab	24.2 ± 3.0	0.105 ± 0.01^b	50.4 ± 2.1	45.0 ± 1.7^ab	42.4 ± 1.4^ab
MW2	31.0 ± 1.8^ab	22.1 ± 2.5	0.122 ± 0.04^ab	49.8 ± 3.2	46.4 ± 2.9^ab	44.0 ± 2.9^ab
MW4	29.7 ± 1.2^ab	24.1 ± 2.8	0.011 ± 0.02^ab	50.0 ± 2.6	46.1 ± 2.2^ab	43.5 ± 2.1^ab
MW6	26.0 ± 3.6^bc	26.1 ± 2.7	0.094 ± 0.02^b	47.5 ± 5.1	43.0 ± 5.8^b	40.5 ± 5.6^b

Mean in the same column with different letters differ (p < 0.05).

1 Different treatments were as follow: untreated = intact whole cottonseed, R15 = roasting for 15 minutes, R30 = roasting for 30 minutes, γ15 = 15 kGy gamma irradiation, γ30 = 30 kGy gamma irradiation, γ45 = 45 kGy gamma irradiation, MW2 = microwave irradiation for 2 minutes, MW4 = microwave irradiation for 4 minutes, MW6 = microwave irradiation for 6 minutes.

2 a = wash out fraction degradation, b = potentially degradable fraction, c = rate constant of degradation of b fraction.

Table 3. Rumen degradation parameters of crude protein of untreated and physically treatedf cottonseed.

	Degradation parameters^2			Effective degradability at outflow rate (g/kg)
Treatments^1	a (g/kg)	b (g/kg)	c (h^−1)	0.02 h^−1	0.05 h^−1	0.08 h^−1
Untreated	46.6 ± 2.5^a	44.6 ± 3.7^a	0.132 ± 0.01^a	85.3 ± 2.8^a	78.9 ± 2.9^a	74.3 ± 3.1^a
R15	45.4 ± 2.5^bc	45.3 ± 3.2^d	0.109 ± 0.02^b	83.5 ± 2.9^ab	76.2 ± 3.0^ab	71.3 ± 2.2^ab
R30	39.1 ± 2.2^cd	50.3 ± 2.6^bc	0.091 ± 0.01^bc	80.3 ± 4.9^bc	71.5 ± 4.8^bc	65.8 ± 4.9^cd
γ15	43.9 ± 1.2^ab	47.3 ± 4.6 ^cd	0.114 ± 0.01^ab	84.1 ± 3.4^ab	76.7 ± 2.5^ab	71.6 ± 2.9^c
γ30	39.6 ± 4.1^cd	49.6 ± 4.8^bc	0.090 ± 0.01^bc	80.1 ± 3.7^bc	71.4 ± 3.8^bc	65.7 ± 2.0^cd
γ45	35.1 ± 3.3^de	53.9 ± 3.4^ab	0.072 ± 0.01^c	77.2 ± 2.8 ^d	66.8 ± 2.6^cd	60.6 ± 3.7^d
MW2	42.1 ± 2.6^c	48.0 ± 4.0^bc	0.114 ± 0.01^ab	82.9 ± 1.0^bc	75.4 ± 1.0^ab	70.2 ± 2.4^bc
MW4	38.3 ± 4.2^de	52.1 ± 1.6^ab	0.098 ± 0.01^bc	81.5 ± 4.3^bc	72.7 ± 4.2^bc	66.9 ± 1.3^cd
MW6	33.1 ± 3.9^d	56.7 ± 3.1^a	0.078 ± 0.01^c	78.0 ± 3.1 ^cd	67.4 ± 2.5^d	60.8 ± 4.2^d

Mean in the same column with different letters differ (p < 0.05).

1 Different treatments were as follow: untreated = intact whole cottonseed, R15 = roasting for 15 minutes, R30 = roasting for 30 minutes, γ15 = 15 kGy gamma irradiation, γ30 = 30 kGy gamma irradiation, γ45 = 45 kGy gamma irradiation, MW2 = microwave irradiation for 2 minutes, MW4 = microwave irradiation for 4 minutes, MW6 = microwave irradiation for 6 minutes.

2 a = wash out fraction degradation, b = potentially degradable fraction, c = rate constant of degradation of b fraction.

Table 4. In vitro protein digestibility of untreated and physically treated cottonseed.

Treatments^1	Protein digestibility in vitro (g/kg)
Untreated	55.6 ± 1.8^c
R15	57.0 ± 2.3^b
R30	58.9 ± 2.5^ab
γ15	56.4 ± 1.4^bc
γ30	58.7 ± 1.5^ab
γ45	59.8 ± 1.8^a
MW2	56.3 ± 2.8^bc
MW4	56.1 ± 2.0^bc
MW6	58.8 ± 2.1^ab

Mean in the same column with different letters differ (p < 0.05).

1 Different treatments were as follow: untreated = intact whole cottonseed, R15 = roasting for 15 minutes, R30 = roasting for 30 minutes, γ15 = 15 kGy gamma irradiation, γ30 = 30 kGy gamma irradiation, γ45 = 45 kGy gamma irradiation, MW2 = microwave irradiation for 2 minutes, MW4 = microwave irradiation for 4 minutes, MW6 = microwave irradiation for 6 minutes.